I'm struggling with the concept of primitive roots and their application in certain proofs. I'm struggling with starting this problem:

Let a and n be in the natural numbers and let p be an odd prime where p does not divide a. Using primitive roots show $\displaystyle x^2 \equiv a $ mod p is solvable if and only if $\displaystyle y^2 \equiv a $ mod p^n is solvable.

Thanks in advance!